1. Field of the Invention
The present invention is related to a biomarker for detection of tumor, especially related to a biomarker for diagnosis of canine cancer.
2. The Prior Arts
Canine cancer is a common leading cause of canine death.
Canine transmissible venereal tumor (CTVT) is naturally occurring, low differentiation round tumor cells. It can be transmitted through allograft (for example, via direct tumor cell transplantation during coitus or via activities such as licking, sniffing, biting, scratching and others), wherein the tumor cells contact wounded mucous membrane or skin and consequently resulting in infection. Furthermore, experiments have demonstrated xenograft transmission. Currently, canine CTVT has been demonstrated to cross transmitted to fox, gray wolf, and immunodeficient mouse. Because this type of tumor can evolve various mechanisms to escape host immune system's monitoring and induced immune response, exhibiting unique growth curve in growth phase and natural regression phase, therefore, it is frequently used as an animal model to study tumor treatment mechanism.
Mammary gland tumor (MGT) frequently occurs in female canine, its prevalence is about 42% of all canine cancer, and is about 82% of female genatile organ derived cancer. In addition, most MGT occurs in 8 to 10 year-old female canine, while MGT in male canine is less common, if occurs, normally companion with abnormal hormone secretion. Traditionally, MGT is classified into two groups based on histopathology and cancer cytology, namely benign and malignant tumor. Benign tumor is reported to be about 40˜50% of the cancer, in which its clinical characteristics include small volume, well embedded, existence for many years and slow growth. Malignant tumor is about 50˜60%, and its clinical symptoms include rapid growth, no covering, ulcer or fever, lymph node invasion and transmission to remote organs, with lung as highest transmitted organs. Distant metastasis of MGT will eventually result in inhibition of organ functions or failure, which is also the main cause of canine death.
Although benignancy or malignancy of CTVT and MGT can be distinguished based on tumor characteristics, cytology and histopathology diagnosis, diagnosis by human judgment may be influence by pathologist's experience and objective opinions. A biomarker is an important tool to detect and trace human diseases as well as critical index in cancer diagnosis. However, there is rare, if any, biomarker(s) designated as tumor marker in canine tumor diagnosis in clinical application. Thus, development of rapid and correct diagnostic method and biomarker(s) will be helpful to determine if a canine is suffered with cancer.